THE Nato military alliance begins a three-day summit in Washington DC tomorrow.

Nato’s ranks have grown from its original 12 nations that signed the Washington Treaty 75 years ago — to 32 countries after Sweden joined this year.

Article 5 of the treaty is a political commitment by all member countries to come to the aid of any member whose sovereignty or territory might be under attack. 

The doors of the military alliance are open to any European country that wants to join and can meet the requirements and obligations but only if every current member is in agreement.

The summit is likely to focus on ways to reassure Ukraine of Nato’s continuing support in the face of Russia’s invasion — a conflict that many experts have attributed to the alliance’s eastward expansion.

The Ukrainians have been pushing for Nato membership which would likely bring them under the umbrella of Article 5. 

Some members of Nato — notably the United States, Britain, France and Germany — are already supplying weapons that Ukraine is using to fight the Russians.

Nato recently agreed that outgoing Dutch Prime Minister Mark Rutte would replace its current secretary general — former Norwegian prime minister Jens Stoltenberg — when his term ends on October 1.

But the real power in Nato rests in the US. The organisation’s military headquarters is based in Mons, Belgium, and is always run by a top US officer. The current supreme allied commander in Europe is Army General Christopher Cavoli.

At the Washington summit Nato leaders will likely endorse a new plan to co-ordinate the delivery of equipment to Ukraine and training for its armed forces. 

The leaders are likely to renew a vow that Ukraine will join the military alliance one day, but not while it’s at war.